Temperature gradient in a ferromagnetic conductor may generate a spontaneous transverse voltage drop in the direction perpendicular to both magnetization and heat current. This anomalous Nernst effect (ANE) has been considered to be proportional to themagnetization1-7, and thus observed only in ferromagnets, while recent theories indicate that ANE provides a measure of the Berry curvature at the Fermi energy EF 8, 9. Here we report the observation of a large ANE at zero field in the chiral antiferromagnet Mn3Sn10. Despite a very small magnetization ∼ 0.002 μB/Mn, the transverse Seebeck coefficient at zero field is ∼ 0.35 μV/K at room temperature and reaches ∼ 0.6 μV/K at 200 K, comparable with the maximum value known for a ferromagnetic metal. Our first-principles calculation reveals that the large ANE comes from a significantly enhanced Berry curvature associated with theWeyl points nearby EF 11. The ANE is geometrically convenient for the thermoelectric power generation, as it enables a lateral configuration of the modules to efficiently cover the heat source6. Our observation of the large ANE in an antiferromagnet paves a way to develop a new class of thermoelectric material using topological magnets to fabricate an efficient, densely integrated thermopile.
|Publication status||Published - 2017 Sep 19|
ASJC Scopus subject areas